/**
 * Software License, Version 1.0
 * 
 * Copyright 2003 The Trustees of Indiana University. All rights reserved.
 * 
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 * 
 * 1) All redistributions of source code must retain the above copyright notice,
 * the list of authors in the original source code, this list of conditions and
 * the disclaimer listed in this license; 2) All redistributions in binary form
 * must reproduce the above copyright notice, this list of conditions and the
 * disclaimer listed in this license in the documentation and/or other materials
 * provided with the distribution; 3) Any documentation included with all
 * redistributions must include the following acknowledgement:
 * 
 * "This product includes software developed by the Community Grids Lab. For
 * further information contact the Community Grids Lab at
 * http://communitygrids.iu.edu/."
 * 
 * Alternatively, this acknowledgement may appear in the software itself, and
 * wherever such third-party acknowledgments normally appear.
 * 
 * 4) The name Indiana University or Community Grids Lab or NaradaBrokering,
 * shall not be used to endorse or promote products derived from this software
 * without prior written permission from Indiana University. For written
 * permission, please contact the Advanced Research and Technology Institute
 * ("ARTI") at 351 West 10th Street, Indianapolis, Indiana 46202. 5) Products
 * derived from this software may not be called NaradaBrokering, nor may Indiana
 * University or Community Grids Lab or NaradaBrokering appear in their name,
 * without prior written permission of ARTI.
 * 
 * 
 * Indiana University provides no reassurances that the source code provided
 * does not infringe the patent or any other intellectual property rights of any
 * other entity. Indiana University disclaims any liability to any recipient for
 * claims brought by any other entity based on infringement of intellectual
 * property rights or otherwise.
 * 
 * LICENSEE UNDERSTANDS THAT SOFTWARE IS PROVIDED "AS IS" FOR WHICH NO
 * WARRANTIES AS TO CAPABILITIES OR ACCURACY ARE MADE. INDIANA UNIVERSITY GIVES
 * NO WARRANTIES AND MAKES NO REPRESENTATION THAT SOFTWARE IS FREE OF
 * INFRINGEMENT OF THIRD PARTY PATENT, COPYRIGHT, OR OTHER PROPRIETARY RIGHTS.
 * INDIANA UNIVERSITY MAKES NO WARRANTIES THAT SOFTWARE IS FREE FROM "BUGS",
 * "VIRUSES", "TROJAN HORSES", "TRAP DOORS", "WORMS", OR OTHER HARMFUL CODE.
 * LICENSEE ASSUMES THE ENTIRE RISK AS TO THE PERFORMANCE OF SOFTWARE AND/OR
 * ASSOCIATED MATERIALS, AND TO THE PERFORMANCE AND VALIDITY OF INFORMATION
 * GENERATED USING SOFTWARE.
 */
package cgl.narada.matching.regex;

import java.util.Enumeration;
import java.util.Hashtable;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

import cgl.narada.event.NBEvent;
import cgl.narada.event.TemplateProfileAndSynopsisTypes;
import cgl.narada.matching.MatchingTree;
import cgl.narada.matching.Profile;
import cgl.narada.matching.ProfileCounts;
import cgl.narada.protocol.Destinations;
import cgl.narada.protocol.ProfilePropagationProtocol;

/**
 * This class implements the RegEx matching algorithm. This provides methods to
 * add a subscription and also to remove interest in a subscription predicate.
 * The matching algorithm should also be able to compute destinations.
 * 
 * @author Shrideep Pallickara $Revision$ $Date$
 */

public class RegExMatching implements MatchingTree, RegExMatchingDebugFlags {
    /** Profile Propagation Handler */
    private ProfilePropagationProtocol profilePropagationProtocol;

    /** The unit level for this matching tree */
    private int unitLevel;

    /** The system level */
    private int systemLevel;

    /** The destination for this node */
    private Destinations thisDestination;

    private Hashtable profilesAndDestinations, profileIds;

    /** No need to match profiles registered to this destination. */
    private int ignoreDestination=0;
    
    private String moduleName = "RegExMatching: ";


    /** The RegExMatching constructor */
    public RegExMatching(int unitLevel, int systemLevel,
            ProfilePropagationProtocol profilePropagationProtocol) {
        this.unitLevel = unitLevel;
        this.systemLevel = systemLevel;
        this.profilePropagationProtocol = profilePropagationProtocol;
        profilesAndDestinations = new Hashtable();
        profileIds = new Hashtable();
    }


    /**
     * This method returns the level assocaited with this matching tree. A node
     * could be a gateway at multiple levels. How it handles destinations at
     * different levels, and propagates destinations at different levels is
     * dicatated by the level of the matching tree which computes the
     * destinations and initiates profile propagation changes.
     * 
     * @return The level of the matching tree.
     */
    public int getMatchingLevel() {
        return unitLevel;
    }


    /** This method sets the destination address for this node */
    public void setNodeDestination(Destinations destination) {
        thisDestination = destination;
        ignoreDestination = destination.getDestinationsAtLevel(unitLevel);
    }


    /**
     * This method adds a subscription predicate to the matching tree
     * 
     * @param profile
     *            The predicate comprising the subscription and the destination
     *            assocaited with the subscription.
     */
    public void addSubscriptionProfile(Profile profile) {
        RegExProfile regExProfile = (RegExProfile) profile;
        String profileId = regExProfile.getProfileId();
        if (profileId == null) {
            System.out.println(moduleName + "Profile Id is NULL in profile "
                + profile);
            return;
        }

        if (profileIds.containsKey(profileId)) {
            System.out.println(moduleName + "Profile " + profile
                + " has already been added ");
            return;
        }
        profileIds.put(profileId, profile);
        /**
         * add the id to list of id's being maintained
         */
        ProfileCounts _profileCounts;
        Object _subscription = profile.getSubscription();

        /**
         * Each subscription has a list of destinations and counts/destination
         * associated with it. If this subscription already exists, update
         * profile counts associated with the entry. Otherwise, simply create a
         * new entry
         */
        if (profilesAndDestinations.containsKey(_subscription)) {
            _profileCounts =
                (ProfileCounts) profilesAndDestinations.get(_subscription);
        } else {
            _profileCounts = new ProfileCounts();
            profilesAndDestinations.put(_subscription, _profileCounts);
        }
        _profileCounts.incrementCountForDestination(profile.getDestination());
    }


    /**
     * This method removes a subscription predicate to the matching tree
     * 
     * @param profile
     *            The predicate comprising the subscription and the destination
     *            assocaited with the subscription.
     */
    public void removeSubscriptionProfile(Profile profile) {
        String profileId = profile.getProfileId();
        if (profileId == null) {
            System.out.println(moduleName + "Profile Id is NULL in profile "
                + profile);
            return;
        }

        if (!profileIds.containsKey(profileId)) {
            System.out.println(moduleName + "Profile " + profile
                + " is not listed here");
            return;
        }

        profileIds.remove(profileId);
        /**
         * remove id from list of id's being maintained
         */

        Object _subscription = profile.getSubscription();
        /**
         * Each subscription has a list of destinations and counts/destination
         * associated with it. Update destinations associated with subscription.
         * If destinations has reduced to zero remove the entry.
         */
        ProfileCounts _profileCounts =
            (ProfileCounts) profilesAndDestinations.get(_subscription);
        boolean delete = false;
        delete =
            _profileCounts.decrementCountForDestination(profile
                .getDestination());
        if (delete) {
            profilesAndDestinations.remove(_subscription);
            if (RegExMatching_Debug) {
                System.out.println(moduleName + "Entry [" + _subscription
                    + "] removed");
            }/* debug */
        }
    }


    public void propagateChangesToHigherLevels(Profile profile,
                                               boolean addProfile) {
        RegExProfile regExProfile = (RegExProfile) profile;

        /**
         * The first step ofcourse is to replace lower level destinations with
         * the destination ID at the next higher level
         */
        if (RegExMatching_Debug) {
            System.out.println(moduleName
                + "The destination associated with predicate "
                + regExProfile.getSubscription() + " is "
                + regExProfile.getDestination());
        }

        int temp = unitLevel;
        int tempDest;
        for (; temp < systemLevel;) {
            tempDest = thisDestination.getDestinationsAtLevel(temp);
            if (RegExMatching_Debug) {
                System.out.print("This destination would be replaced by "
                    + tempDest);
            }
            temp++;
            if (RegExMatching_Debug) {
                System.out.println(" for representation in a level(" + temp
                    + ") tree ");
            }

            RegExProfile _propagateRegExProfile =
                new RegExProfile((String) regExProfile.getSubscription(),
                                 tempDest, regExProfile.getProfileId());

            profilePropagationProtocol
                .propagateProfileChange(_propagateRegExProfile, temp,
                                        addProfile);
        }
    }


    /**
     * This method return the destinations assocaited with an event that needs
     * to be matched to the matching tree
     * 
     * @return The destination as an INT
     */
    public Object matchEvent(NBEvent nbEvent) {

        String contentSynopsis = (String) nbEvent.getContentSynopsis();
        int destinations = ignoreDestination;

        Enumeration _profiles = profileIds.elements();
        while (_profiles.hasMoreElements()) {
            RegExProfile regExProfile = (RegExProfile) _profiles.nextElement();
            int dest = regExProfile.getDestination();
            if ((dest & destinations) != 0) {
                continue;
            }
            Pattern regExPattern = regExProfile.getPattern();
            if (evaluateRegExOnInput(regExPattern, contentSynopsis)) {
                destinations = destinations | dest;
            }
        } /* end while */

        return new Integer(destinations);
    }


    public boolean evaluateRegExOnInput(Pattern regExPattern,
                                        String contentSynopsis) {
        System.out.println(moduleName + "Matching Event at unit level "
                           + unitLevel);
        Matcher matcher = regExPattern.matcher(contentSynopsis);
        matcher.reset();
        return matcher.find();
    }


    /** Returns the type of profiles managed by this matching engine */
    public int getManagedProfileType() {
        return TemplateProfileAndSynopsisTypes.REGULAR_EXPRESSIONS;
    }


    public static void main(String[] args) {
    }

}
